1. Field of the Invention
The present invention relates to a straddle-type vehicle that is improved in the arrangement of an automatic transmission control unit.
2. Description of the Related Art
Known straddle-type vehicles include motorcycles. Motorcycles generally have a transmission. The rotation of the crankshaft of an engine is changed by the transmission and transmitted to a powered wheel. The transmission includes a shift mechanism having a main shaft, a drive shaft, and a multiple-step speed change gear, and a clutch mechanism that interrupts the transmission of the rotation at the switching of the speed change gear. Another known motorcycle has an automated manual transmission mechanism for automatically operating the clutch mechanism and switching the speed change gear of the transmission (for example, see Japanese Patent Publication No. JP-A-2003-320861 (pp. 1-6, FIGS. 1-7)).
Since the shift actuator of the conventional automated manual transmission mechanism has been disposed behind the engine and directly on the engine, the shift actuator is vulnerable to the heat and vibration of the engine. Also, since the shift actuator has been disposed between the engine and the body frame, a space for the shift actuator has been needed between the engine and the body frame, thus posing the problem of difficulty in reducing the size of the entire vehicle.